What happens to the LED in a temperature-controlled circuit when the temperature rises?

In a temperature-controlled circuit, typically designed for temperature sensing and control, the behavior of components like an LED is influenced by changes in temperature. In this case, as the temperature rises, the MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) may turn on, depending on the circuit design and the specific temperature characteristics of the components involved.

When the temperature exceeds a certain threshold, the increase in temperature can cause the MOSFET to enter a conductive state, allowing current to flow through the LED. This current flow will cause the LED to light up, indicating that the circuit is responding to the higher temperature. The MOSFET essentially acts as a switch that controls the LED’s operation based on temperature input.

The other options suggest different behaviors which do not align with how temperature-controlled circuits typically operate. For example, an increase in resistance due to temperature generally doesn't apply to a circuit designed to activate an LED in response to a temperature rise.